A bolometer is a device that can detect electromagnetic radiation according to measurable changes in the physical properties of a material that absorbs the radiation. The absorbing material may, for example, experience an increase in temperature when irradiated with electromagnetic energy that affects the resistance of the material. Accordingly, some bolometers measure the resistance of a piece of absorbent material having known dimensions and under controlled conditions to extrapolate a determined amount of electromagnetic radiation being absorbed by the material, and by extension, an amount of electromagnetic radiation present in the vicinity of the absorbent material.
Bolometers are often used in photodetectors for electronic devices configured to measure thermal radiation. For example, certain types of night vision sensors employ bolometer based photodetectors at each pixel to detect infrared light. Bolometers currently available are limited in the available applications, however, due to the fact that they only detect radiation within a narrow band of the wavelengths that represent thermal energy. Moreover, many of the bolometers currently available become less-sensitive at ambient temperatures (e.g., 200-300 K).
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.